Cold air return – proximity to furnace
Cold air return – proximity to furnace intake.
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I am finishing a basement and with new walls around the furnace and hot water heater. Both have visible air intakes inside the house and have exhausts plumbed out the side of the house.
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The cold air return in the basement is currently on the ceiling. I plan to route it down closer to the floor with the intake being on the larger room side of the basement.
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I will install vents in the walls so that the room enclosing the furnace and water heater will be well ventilated.
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Now there will be a door between the cold air intake and furnace intake but physically they are still close. I seem to recall discussion in the past which warned of a potential hazard to doing this. A search didn’t find the discussion I was looking for.
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Replies
bump
Well let's try this again.
Com'n guys, this is a real need here.
sobriety is the root cause of dementia.
that one has to have a bunch more of "more information" and needs to be seen..
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
Forget the primal scream, just ROAR!!!
I'm not able to visualize this situation from his description.
Yeah, sounds like he has his furnace exhaust shooting out the side of the house.
I think he's saying there is a cellar ceiling cold air vent going to the first floor that is close to an air vent on the furnace room wall in the cellar and he's concerned over this possibly being a fire hazard.
He's been around since '01 so hopefully he'll check back in here and supply some details.
Cheers
sobriety is the root cause of dementia.
No, he is talking about a cold air return to the furance.You don't want it close to the furnaces, WH, as it can cause back drafting.I believe that codecheck.com (Sample book) has the basic specs. Don't know how the door fits in, which I think is what he asking aobut.
Ah, I see.
Where is Asennad?
sobriety is the root cause of dementia.
Re bump: sorry, I didn't see this one:
>>Now there will be a door between the cold air intake and furnace intake
You meant "cold air return," right?
Rule of thumb, return not within 8' of the furnace.
If the cold air return depressurizes the space around the furnace, there can be backdrafting and/or excessive carbon monoxide production.
Practical reality: you have to test with a draft gauge.
The size of the adjacent spaces, the tightness of the house, the configuration of the house and the other competing devices "pushing" air out of the house can and will all effect the operation.
I have done draft tests where pulling the cover off of the blower compartment a foot or so below the drafthood didn't affect the draft (typically pre-mid-70's houses where the furnace was in a big empty basement); I've also done tests where turning on a bathroom fan a couple of floors away has affected the draft (typically later, well built tight houses.)
I re-tested a "fixed" installation (on my inspection I had noted insufficient (read "none") combustion air for a 100000btu natural draft furnace in a 7x12 room with a dryer - an HVAC guy* added one undersized vent to the bottom of the door (6x13" with a cover on each side.)
The furnace vented OK when operated alone; the draft dropped slightly when a nearby bathfan was turned on; the draft dropped significantly and the CO levels soared dangerously in the furnace when the dryer was started.
The venting tables typically used note that they are for "standard installations" but that other factors may affect the draft and the "designer" of the system is responsible for whether it actually works!
In other words: TEST!
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*This was the guy who. per the owner, had been servicing the furnace for years and apparently never noticed there wasn't any air supply to the utility room!
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